Hygroscopic steam valve



Oct. 15, 1957 EL ROY J. KRAFT 2,309,654

HYGROSCOPIC STEAM VALVE Filed Sept. 10, 1954 2 Sheets-Sheet I EL EHZUF [Lay J. Kraff Oct. 15, 1957 EL ROY J. KRAFT HYGROSCOPIC STEAM VALVE 7 2 Sheets-Sheet 2 Filed Sept. 10, 1954 VII 4.

&m

VIII-IF! llll hex-22272 575 J. Rm?! 1 nronoscorrc STEAM VALVE E1 Roy J. Kraft, Des Plaines, 111., assignor to The Dole Vaive Company, Chicago, 111., a corporation of Illinois Application September 10, 1954, Serial No. 455,288

6 Claims. (Cl. 137-197) The present invention relates to an improved steam valve for venting air trapped in radiators being heated by circulating steam.

In heating systems utilizing steam as a heating media, it is highly desirable that entrapped air be vented from the system, or more specifically, from the closed fluid circuit through which the heating media is circulated. To accomplish that objective vent valves are sometimes used at the radiators, however, the valve must necessarily be capable of preventing the liberation of an excessive amount of condensed steam into the room being temperature conditioned.

One of the better types of steam valves presently being used is the type shown as the hygroscopic valve in which a plurality of hygroscopic discs or washers are used to control a. venting passage. These hygroscopic elements have the characteristic of swelling when in contact with water, means are provided to cause the swelling of the elements to close off the venting passage entirely. After a suflicient time has elapsed to permit the hygroscopic elements to return to their normal size, the valve is again capable of venting air.

While this new type of valve operates satisfactorily over a reasonably wide range of water contents, a particularly high water content may have the elfect of swelling up the hygroscopic elements and maintaining their swell for an excessive period of time. Frequently, these abnormal moisture contents are strictly temporary, but nevertheless keep the hygroscopic elements swollen for a considerable period of time with the result the valve is inoperative for a substantial period of time.

One of the primary objects of the present invention is to provide an improved vent valve of the hygroscopic type which will respond rapidly to conditions of excess moisture, and which will effect a shorter drying cycle than hygroscopic valves now being employed.

Another object of this invention is to provide a venting valve from which moisture may be liberated rapidly from hygroscopic elements.

The present invention can best be understood by reference to the attached sheets of drawings which illustrate several preferred forms of the invention.

In the drawings:

Figure 1 is a view in elevation of the vent valve, with the hygroscopic elements removed;

Figure 2 is a cross-sectional view on a greatly enlarged scale, of the vent valve;

Figure 3 is a view similar to Figure 2 but illustrating the condition of the hygroscopic elements after they become swollen by coming in contact with water;

Figure 4 is a cross-sectional view of a modified form of valve;

Figure 5 is an exploded view of the elements shown in Figure 4; and

Figure 6 is a cross-sectional view taken substantially along the lines VIVI of Figure 4.

As shown in the drawings:

In Figure 1, reference numeral 10 indicates generally 2,809,654 Patented Oct. 15, 1957 ice a vent valve embodying the present invention, the valve 10 including a body member 11 having a reduced diameter neck formed with a tapered, threaded shank portion 12 arranged to be received within a similarly threaded portion in a steam radiator. The body member 11 is also provided with an enlarged tool engaging portion 13 of generally hexagonal shape.

The body member 11 is provided with an internally threaded axial bore 14 which is arranged to receive the threaded end portion 16a of a bushing 16. The bushing 16 has an axial bore 16b forming a passage through which gaseous fluid is vented to a pair of ports 16c communieating with a space 12:: separating the bushing 16 from the walls of the body member 12.

The bushing 16 is formed with an enlarged head portion 160. and, disposed between this enlarged head portion 16d and the body member 11 are a plurality of hygroscopic discs or washers 17. Preferably, the material making up the Washers 17 expands to at least about 130% of its original thickness when immersed in water at room temperature for approximately one (1) hour. When dried at room temperature for a period of approximately one (1) hour, the material should be capable of returning to within about of its original thickness. The washer 17 can, for example, be composed of an unglazed, uncalendered vulcanized fibre composition.

Surrounding the washers 17 is a foraminous cylindrical sleeve 15 including a plurality of spaced openings 13a. The sleeve 18 is preferably composed of some non-corroding metal such as brass. As will be noted, the openings 13a are of substantial size and are closely spaced to provide a maximum proportion of open area.

The head portion 16d is provided with an annular recess 16:11, having an inner side wall 16:12, an outer tapered side wall 16:13 and a bottom wall 16a'4.

The body member 11 is correspondingly recessed as at 11a to provide an inner side wall 11b, a tapered outer side wall 11c and a bottom wall lid.

The sleeve 18 embraces the side walls 16512 and 11b and the ends of the sleeve bottom against the bottom walls 16th and 11a. The tapered side walls 16x13 and 11c facilitate easy assembly. Axial advance of the bushing 16 in the body member 11 by virtue of the interengage ment of screw threads 15 formed therebetween, will clamp the sleeve 18 in firm assembly with the body 11 and the bushing 16 without requiring the use of any supplemental fastening means.

The sleeve 18, therefore, not only forms a protective cage for the hygroscopic material but maximizes the available open area so that drying time will be reduced.

As best seen in Figure 2, the normal diameter-of the inner annular edges of the washers 17 is somewhat greater than the diameter of the shank portion 16a of the bushing 16. The outer peripheral diameter of the washers 17 is also significantly less than the inner diameter of the perforated sleeve 18. Hence, when the washers 17 are dry as shown in Figure 2, gaseous fluids pass from the space 1211, through the passage 1212 around the shark 16a and will also pass through the relatively porous washers 17 into the atmosphere through the openings 13a. When steam first arrives at the valve, however, the cool surfaces of the valve cause the steam to condense, and to swell the washer 17.

After prolonged use of the valve suflicient moisture will be trapped within the washers 17 to cause the washers to expand or swell and fill completely the space between the bushing 16 and the sleeve 18. This condition is illustrated in Figure 3 of the drawings. When this condition is reached, the valve is substantially inoperative for the purpose of venting gases to the atmosphere, until such time as the washers 17 have dried out sufiiciently to tend back to their normal dimensions. The provision of the foraminous sleeve 18 .greatly facilitates the drying of the washers 17 by providing an exceedingly large open area through which the moisture trapped in the washers 17 can be liberated to the outside atmosphere.

A furthenmodified form of the invention is shown in Figures 4 to 6 of the drawings. :This form of the invention is generally similar to that already described but includes additional features to maximize the fastest possible drying of the hygroscopic material and includes a body member 21 having a threaded end portion 22 arranged to be 'received Within the steam radiator. The body member 21 has a round'central bore 21a which is arranged to receive a square, threaded end of a shank 23a of a bushing 23. As seen in Figure 6, the provision of a square threaded shank into the round bore 2la'leaves spaces 24 forming flow passages in fluid communication with axial bore 22:: formed'in the-end portion 22. The bushing 23 includes an enlarged end portion 23b in which is formed a slot 230 of 'asize permitting the'insertion of a screw driver for purposes of positioning the bushing 23within the body member 21.

Disposed between the enlarged end portion 23b and the body member 21 and compressed therebetween are a plurality of relatively large diameter hygroscopic washers 26 in alternate series with'a plurality of relatively small diameter hygroscopic washers 27. Each of the washers 26 and 27 are separate and may be stacked together into a column as best seen in the exploded View of Figure 5.

A foraminous sleeve 29 is provided in circumscribing relation to the stack of interleaved washers 26 and 27. The sleeve 29 is secured to the valve member by closely fitting the sleeve on a suitable shoulder 21b provided in the body member 21 and on a suitable corresponding shoulder 23171 formed on the enlarged portion 23b.

The arrangement of hygroscopic washers illustrated in Figures 4 and maximizes surface area of the washers exposed to the atmosphere so that the length of time of the drying cycle of the washers is reduced. Thus, the valve is restored to venting condition in shorter periods of time, a particularly valuable feature Where the valve is included in an automatic heating system.

Although various minor modifications might occur to those versed in the art, it should be understood that 1 wish to embody within the scope of the patent warranted hereon all such modifications as come within the scope of my part having an internally threaded axial bore formed therein, and a bushing providing said second part having a threaded shank and an enlarged radially outwardly extending head 'portion formed atone end thereof, a cylindrical'foraminous sleeve concentrically outwardly of said shank having closely spaced openings formed therein and being bottomed at one end against said head portion and being bottomed at its opposite end against said body member, said shank being threaded into said axial bore sulficiently to clamp said sleeve in firm assembly with said body member and said bushing, thereby to form an annular space around said shank, a plurality of washers made of porous hygroscopic material inside of said annular space, said washers when dry having inner annular edges of a diameter greater than the diameter of said shank, thereby to form with said shank an annular passage communicating with the atmosphere through said porous hygroscopic material of the washers and with the openings of said sleeve, and means forming a longitudinally extending venting passag'e'from one end of'said parts into'said annular passage, whereby steam passing through said venting passage will be condensed by the relatively cool surfaces of said valve and the liquid condensate will swell the washers to completely fill said annular space, thereby to close said annular and venting passages for inactivating said valve against further venting of air until said washers are restored in size by drying.

2. A venting valve as defined in claim 1, said means forming a longitudinally extending ventingpassage comprising a passage'for-med by an axially extending bore in said shank.

3. A venting valve as defined in claim 1, said axial bore of 'sai'dbody'member being round said shank of said bushing being square,'thereby'leaving axial extending spaces between said shank and said body member providing said means forming a longitudinally extending venting passage.

4. A venting-valve comprising a body member including a venting passageway having'an inlet and an outlet, a bushing adjustably positionable within said body member, and a plurality of individual-hygroscopic elements positioned at the outlet of said venting passageway between said body member and said bushing, said hygroscopic elements being a-series of disks of varying dimensions, and a foraminous outer sleeve about said hygroscopieelementsforming an annular confining cage for said elements whereuponswelling of said elements in response to Wetting thereof will completely fill the cage thereby closing oil the outlet of the venting passageway and inactivating-said valve for further venting of air until said disks are dried.

5. A venting valve comprising a body member, a bushing adjustably positionable within said body member, and a plurality of individual hygroscopic elements compressible' between said body member and said bushing, said hygroscopic'elements including a plurality of relatively large diameter disks and a plurality of smaller diameter 'fill said annular space. thereby to close said annular. space and said venting passage-and inactivating said valve. for further venting of air until said washers are restored to smaller size by drying.

6. A-venting valve as described in claim 1, said head' portion beingjprovided :with an annular recess having an inner side wall, anouter tapered side wall and a bottom wall, said body member being correspondingly recessed to provide an'annulararecess having an inner :side 'wall, a tapered side wall and a bottom wall, said foraminous sleeve embracing said sidewalls and the opposite ends of said sleeve being bottomed against the respective bottom 7 walls of said annular recesses, said tapered side walls facilitating easy assembly between said "body member, said bushing and said foraminous sleeve.

References Citedin the file of thispatent UNITED STATES PATENTS Grosvenor Oct. 6, i953 Hencken Mar. 23, 1954 

